The present invention relates to methods of treating a gaseous mixture or unprocessed gas by adsorption which employs the selective arrest of at least one component of the said gaseous mixture, which latter is caused to pass through an adsorber containing adsorbent granular material.
In a known form of method of this nature, use is made of three adsorbers which operate in the same cycle with a difference of phase from one to the next, the said cycle comprising:
(A) A HIGH-PRESSURE PRODUCTION PHASE DURING WHICH A TREATED GAS IS WITHDRAWN WHICH RESULTS FROM PASSING THE SAID MIXTURE THROUGH A FIRST ADSORBER IN A DIRECTION TERMED THE PRODUCTION DIRECTION AT VIRTUALLY CONSTANT PRESSURE,
(B) A PHASE OF REGENERATING THE FIRST ADSORBER, CONSISTING FIRSTLY OF DE-PRESSURISATION FROM THE HIGH PRODUCTION PRESSURE TO A LOW REGENERATION PRESSURE, THE SAID DE-PRESSURISATION INCLUDING TWO BALANCING OPERATIONS ON THE ONE HAND BETWEEN THE SAID FIRST ADSORBER AND A SECOND ADSORBER WHICH IS BEGINNING ITS RE-PRESSURISATION PHASE AND ON THE OTHER HAND BETWEEN THE SAID FIRST ADSORBER AND A BUFFER CONTAINER, WITH OUTFEED IN THE SAME DIRECTION AS THE PRODUCTION DIRECTION AND INFEED IN THE OPPOSITE DIRECTION, THEN OF CONTINUATION OF THE DE-PRESSURISATION TO THE LOW PRESSURE, AND FINALLY OF A PHASE OF CLEANSING AT THE SAID LOW PRESSURE WHICH IS PERFORMED BY PASSING THROUGH SOME OF THE GAS FROM THE SAID BUFFER CONTAINER IN THE OPPOSITE DIRECTION FROM THE DIRECTION OF PRODUCTION,
(C) A RE-PRESSURISATION PHASE, CONSISTING OF THE SAID BALANCING WITH AN ADSORBER AT THE BEGINNING OF ITS REGENERATION PHASE IN THE OPPOSITE DIRECTION FROM THE DIRECTION OF PRODUCTION, AND OF RE-PRESSURISATION TO THE HIGH PRESSURE BY INTRODUCING TREATED GAS IN THE OPPOSITE DIRECTION FROM THE DIRECTION OF PRODUCTION.
It is an object of the invention to establish a method of the kind described above which enables the following objects to be achieved;
Continuous consumption of unprocessed gas at a constant rate, PA1 Continuous production of treated gas at a virtually constant rate, PA1 Continuous production of residual gas at a virtually constant rate, PA1 Production of treated gas at a pressure very close to that of the unprocessed gas, PA1 Production of residual gas at a pressure which is possibly higher than atmospheric pressure without machinery, PA1 A cycle which enables gas of high purity to be obtained.